Hermetic pump for use in refrigeration systems



June '1, 129265 J. E. EMBURY ETAL 7 HERMETIC PUMP FOR USE IN REFRIGERATION SYSTEMS Filed April 2, 1962 2 Sheets-Sheet 1 l oo okoooo OOOOOOOO INVENTORS. JOSEPH E. EMBURY. LOUIS l'l. LEONARD, JR.

ATTORNEY.

June '1 1965 J. E. EMBURY ETAL 3,186,187

IHE-RMETIC PUMP FOR USE IN REFRIGERATION SYSTEMS Filed April 2, 1962 2 Sheets-Sheet 2 FIG. 2

In Q rm "m b w l l l H 0 H M JOSEPH E. Rs i '3 LOUIS H. LEONARD,JR.

v BY

ATTORNEY.

United States Patent 3,186,187 HERf/EETEC PUMP FOR USE IN REFRIGERATION SYSTEMS Joseph E. Embury, Memphis, and Louis H. Leonard, Jr.,

Dewitt, N.Y., assignors to (Iarrier Corporation, Syracuse, N.Y., a corporation of Delaware Filed Apr. 2, 1962, Ser. No. 184,430 2 (Ilaims. (Cl. 62-483) This invention relates to absorption refrigeration sysstems and, more particularly, to an absorption refrigeration system including a hermetic pump for circulating so lution in the system.

In absorption refrigeration systems employing saline solutions such as a mixture of Water and lithium bromide as an absorbent and water as a refrigerant, circulation of the water-lithium bromide solution throughout the system is usually effected by means of one or more pumps. Common practice utilizes the solution pumped to lubricate and cool the moving parts of the pump such as the bearings, thereby eliminating the higher cost of, and the sealing problems incident to, the use of a pump having a separate lubrication and cooling system.

The use of the solution as a lubricant and coolant for the bearings presents serious problems. Primarily the problems take two main forms, each related to the other. First, due to the copper plating propensities of the solution the pump bearing surfaces may become plated with copper thereby progressively reducing the bearing clearance to a point where seizure occurs. The second prob lem also results directly from the use of the solution as a lubricant and coolant in that as the system operates the solution becomes increasingly contaminated with foreign matter, such as rust, dirt, and abrasives. In relying on a portion of the contaminated solution to lubricate and cool the bearings, momentary failure of the lubricating film and the introduction of foreign matter into the bearings may occur resulting in abrupt increases in friction, and in scoring and galling of the bearing surfaces. The effect on the bearings is evidenced by fluctuations in the pump motor current, the fluctuations emerging as peaks occurring at regular intervals on amperage recording charts. Such fluctuations above normal current load often necessitate use of a thermal protection device in the pump motor windings to prevent possible damage thereto.

It is therefore a primary object of the present invention to provide an absorption refrigeration. system including a pump for circulating solution throughout the system which effectively utilizes the solution itself as a lubricant and coolant for the pump bearings.

A further object is to provide an absorption refrigerant pump having tapered cooperating bearing surfaces with closed end longitudinally extending lubricating recesses in one cooperating bearing surface whereby rotation of the bearing effects direct and complete lubrication of the bearing.

An additional object is to provide a tapered bearing surface in a solution circulating pump having at least one closed end longitudinally extending recess with a solution feeding passage in the surface supporting bearing member communicating with the recess whereby the recess is maintained substantially full of solution, the recess serving upon rotation of the bearing to lubricate the bearing surfaces, thereby preventing scoring and galling of the bearing surfaces. The recess may also serve to entrap foreign particles borne by the solution. Other objects of the invention will be readily perceived from the following description.

This invention relates to an absorption refrigeration system which comprises, in combination, an absorber, an evaporator, vapor from the evaporator flowing to the absorber to be absorbed by solution therein, a condenser,

a generator, Vapor from the generator flowing to the condenser to be condensed therein, condensate from the condenser passing to the evaporator, and means to circulate solution, said means comprising a pump assembly including a pump housing having an inlet and an outlet, an impeller in said housing, a motor for actuating said impeller, a shaft carrying said impeller and connected to said motor, a bearing supporting the shaft in desired position to permit rotation thereof, the bearing including a fixed member and a movable member having cooperating tapered surfaces, recess means in one of said cooperating tapered surfaces with solution carrying passage means in the bearing member communicating with said pump outlet whereby upon rotation of the movable member said recess effects solution lubrication of the bearing.

The attached drawings illustrate a preferred embodiment of the present invention, in which FIGURE 1 is a flow diagram of an absorption refrig eration system including the pump structure of the present invention;

FIGURE 2 is a sectional view of the pump structure;

FIGURE 3 is an enlarged sectional view of the bearing construction; and

FIGURE 4 is a cross sectional view taken along line lV-IV of FIGURE 3.

Referring particularly to FIGURE 1 of the drawing, there is shown an absorption refrigeration machine com prising an absorber section 2 within a shell 3. A plurality of heat exchange tubes 4 are provided within the absorber section. A purge line 5 leads from a suitable region of the absorber and serves to'conduct noncondensible gases therefrom to a suitable purge unit 6. A spray header 7 is located above the absorber section.

Also disposed in shell 3 is an evaporator section 8 comprising a pan-like member 9. In a closed absorption refrigeration system, such as shown here, a plurality of heat exchange tubes 10 are positioned in evaporator section 8. Tubes 10, along with inlet line 48 and outlet line 49, form part of a closed system containing a heat exchange fluid, such as water, which is cooled during passage through tubes 10.

In an open absorption refrigeration system heat exchange tubes 10 and the heat exchange fluid are omitted. Instead, the chilled refrigerant itself is forwarded from evaporator 8 to the area to be cooled by suitable means.

A spray header 1-1 is located above heat exchange tubes 16 for distributing refrigerant thereover. A plurality of eliminators 12 are provided to prevent entrained liquid refrigerant particles being carried from evaporator section 8 to absorber section 2. Evaporator section 8 is in communication with absorber section 2 through eliminators 12. v

In operation, a suitable refrigerant is sprayed over tubes 10 in evaporator section 8 and a suitable absorbent solution is sprayed over tubes 4 in absorber section 2. Discharge of the refrigerant from spray header 1]. flash cools the refrigerant, a port-ion of which vaporizes and passes through eliminators 12 into absorber section 2. The chilled refrigerant in the evaporator section extracts heat from the heat exchanger fluid passing through heat exchange tubes 10 resulting in further vaporization of the refrigerant. This vapor also passes into absorber section 2 through eliminators l2.

A suitable absorbent solution is sprayed over tubes 4 in absorber section 2, the refrigerant vapor being absorbed by the absorbent solution. Cooling fluid passing through heat exchange tubes 4 serves to' extract heat from the vapor. The absorbent solution accumulates in the lower portion of the absorber section 2.

Line 14 is connected to solution recirculation pump 16 and serves to circulate absorbent solution of intermediate strength accumulated in the lower portion of absorber section 2 through line 17 to spray header 7 in order to recirculate absorbent solution in the absorber. A line 18 containing weak solution leads from a lower portion of absorber section 2. Solution pump 19 serves to pass the weak solution through line 20, solution heat exchanger 21, and the line 22 to generator section 26. The specific construction of pump 19 is hereinafter described.

As used herein, the term strong solution refers to an absorbent solution strong in absorbing power and the term weak solution refers to absorbent solution weak in absorbing power. The term intermediate strength solution refers to a solution having a concentration intermediate that of strong solution and weak solution.

A suitable absorbent for a refrigeration system of the type described comprises a hygroscopic aqueous salt solution such as lithium bromide and water. The concentration of the strong solution leaving the generator may be about 65%. A suitable refrigerant is water.

The absorption of refrigerant vapor by absorbent solution in absorber section 2 dilutes the absorbent solution and diminishes the refrigerant supply which must be replenished in order to maintain the refrigeration machine in operation. it is desirable, therefore, to concentrate the weak solution by separating it from the absorbed refrigerant and to return the refrigerant to the evaporator section and the concentrated absorbent solution to the absorber section. For this purpose, a generator section 26 and a condenser section 27 are provided.

Generator section 26 is located in shell 28 and comprises a plurality of tubes 29 for placing steam or other heating fluid in heat exchange relation with solution in the generator. Also located within shell 28 is condenser section 27 comprising a pan-like member 38 within which is disposed a plurality of tubes 31 through which cooling water is passed in heat exchange relation with the refrigerant vapor to condense the same. Eliminators 32 are provided to prevent strong solution from being entrained in refrigerant vapor passed from generator section 26 to condenser section 27.

A line 33 leads from pan-like member to evaporator section 8 and serves to return condensed refrigerant from the condenser section to the evaporator section. The condensate is flash-cooled upon discharge in the evaporator and the cooled liquid refrigerant is distributed over the tubes therein in heat exchange relation with liquid to be cooled passing through the tubes.

Line 34 extends from generator section 26 to solution heat exchanger 21 to absorber section 2 and serves to return relatively hot, strong absorbent solution from the generator section to the absorber section while pass ing it in heat exchange relation with relatively cool, weak solution being forwarded to the generator for concentration thereof.

A bypass line 35 and bypass valve 36 having suitable actuator mechanism may be provided for capacity control of the refrigeration system. Reference is made to Leonard application Serial No. 2,203, filed January 13, 1960, now Patent Number 3,054,272, for a more complete description of the control arrangement.

A steam inlet line 37 and outlet line 38 having suitable steam trap 39 may be provided to admit steam to heat exchange tubes 29 in order to boil off refrigerant vapor from weak solution supplied to the generator thereby concentrating the weak solution. Alternatively, other suitable heating mediums may be employed to heat solution in generator 26.

It will be understood that the vaporized refrigerant passes through eliminators 32 and is condensed in condenser 27. A cooling water inlet line 40 is connected to heat exchange tubes 4 in absorber section 2, the cooling water passing from the absorber through line 41 to heat exchange tubes 31 in the condenser section. The cooling water is then discharged through line 42. A bypass line and valve 43 may be provided to bypass cooling water around the condenser section if desired.

A suitable recirculation line 45 and refrigerant recirculation pump 46 pass refrigerant from pan 9 of the evaporator section through line 47 to spray header 11 so that refrigerant may be sprayed over heat exchange tubes 16 to wet them. Lines 48 and 49 are provided to conduct a heat exchange fluid, such as water, through heat exchange tubes 10 to cool the fluid by the resulting heat exchange with the cooled refrigerant in evaporator 8. This cooled heat exchange fluid is then passed by a pump (not shown) to suitable remotely located heat exchangers to provide cooling in the desired areas.

Referring particularly to FIGURE 2, absorber pump 19 includes a housing 66 having an inlet 61 and an outlet 62. Impeller 63 is placed in the housing and is attached to shaft 64 rotated by motor 65. Motor 65 comprises a rotor 66, connected to shaft 64, and a stator 67 fixedly attached to housing 60. Shaft 64 is supported for rotation by bearing means 68, 69 consisting of conical bearing members 70, 71 attached to shaft 64 and cooperating complementary tapered bearing members 72, 73

Bearing member 72 is slidably positioned with the bearing housing 74. Bearing housing 74 is attached to housing 60. Pin means 77 attaches bearing member 72 to bearing housing 74.

Bearing member 73 is slidably positioned in bearing housing 75. Bearing housing 75 is attached to housing 60. Backing plate 76 is attached to bearing member 73 by pin means 77. Screw means 80 in backing plate 76 cooperate With slot mean 81 in bearing housing 75 to permit limited axial movement of backing plate 76bearing member 73 assembly and to prevent rotational movement of the backing plate 76bearing member 73 assembly. Spring means 78 bears against backing plate 76. Removable housing cover plate 79 bears against the opposite end of spring means 78. This construction permits limited axial adjusting movement of the bearing members 70, 71 with respect to their cooperating bearing members 72, 73 against the bias of spring 7'8 in the event of wear or copper plating of the bearing surface.

Referring particularly to FIGURES 3 and 4 of the drawings, which show enlarged views of the bearing 69, outer bearing member 73 is provided with a plurality of shallow longitudinal recesses 85. Bearing passage means 87 communicate with each recess 85. Radial slots 90 in the rear face of bearing member 73 communicate with each passage means 87 to insure, in a manner hereinafter described, that the recesses at all times remain full of solution. Recess terminal land portions 86 are provided to close off the ends of the recess, reducing undesired flow or pumping of the solution through the bearings to a minimum. It is noted that hearing 68 is similarly constructed having recesses 3%, passage means 83 communicating therewith, radial slots 93 communicating with passage means 88, and terminal land portions 91.

Referring to FIGURE 2, openings 95 are provided in pump body 60. The purpose of the openings 95 is to admit solution from the pump impeller area into the motor area. A further opening exists in the form of clearance 96 between the pump impeller area and bearing 68.

Solution entering openings 95 flows between rotor 66 and stator 67 and to the bearings 63, 69. This flow effects cooling of the motor and cooling and lubrication of the bearings. While a large amount of solution is directed to the motor 65 and bearings 68, 69 solution flow between the bearing surfaces is very slight. The solution which enters passage 97 in bearing housing 75 after leaving motor 65 enters bore 98 in shaft 64. The solution flows to chamber 99 from bore 98 and returns to the pump impeller area by means of passages 180.

A portion of the solution flowing into bore 98 fills radial slots 90 in bearing member 73 of bearing 69. Recesses and passage means 87 communicating individual recesses with corresponding radial slots are filled with solution. It is noted that solution may also enter radial slots 90 through the clearance between bearing member 73-backing plate 76 assembly with the bearing housing 75.

Solution in chamber 99 fills clearance 96 and radial slots 93 in bearing member 72 of bearing 68. Recesses 89 and passage means 88 communicating individual recesses with corresponding radial slots 93 are accordingly filled with solution. Solution may also enter radial slots 93 by means of the clearance between bearing member 72 and bearing housing 74.

Impeller 63 provides the flow pressure necessary to circulate the solution. It is to be emphasized that solution flow through bearings 68, 69 is very slight. Passage means 87, 88 serve to replenish the slight amount of solution lost and to maintain sufficient pressure to insure that bearing recesses 85, 89 are filled with solution.

It will be appreciated that while four recesses have been shown, any number may be utilized. Further, while the slots have been shown as extending longitudinally of the bearings they may extend at any angle to the bearing axis including 90". Finally, the recess and cooperating channel feeding means may be in either or both bearing members.

During operation :of the pump, relative rotation of the bearing surface wipes a film of solution over the surface. The pressure supplied by impeller 63 in addition to normal centrifugal pumping action of the tapered bearing surface is sufiicient to force a slight amount of solution between the bearing land portions. Since circulation of the solution through the bearings is almost negligible, no appreciable pumping of solution occurs. The quantity of solution circulated through the bearing being extremely small, the possibility of solution borne impurities entering the bearing is greatly reduced. The recesses themselves serve to trap the larger impurities in the solution thereby preventing the entry of larger impurities between the bearing surface. To provide more effective filtering of the solution, the recesses may be filled with a porous material.

The present invention provides an extremely simple and economical pump assembly which eliminates a perplexing problem and permits economies in construction of the pump to be effected that could not otherwise be made.

While the preferred embodiment of the present invention discloses a hermetic pump for use in an absorption refrigeration system, the disclosed pump is not limited in use thereto. It Will be understood the pump may be employed as a refrigerant pump or Water pump and in such case refrigerant or the water may be employed as the lubricant and cooling medium rather than solution.

While we have described a preferred embodiment of the present invention, it will be understood that the invention is not limited thereto since it may be otherwise embodied within the scope of the following claims.

We claim:

1. In an absorption refrigeration system, the combination of an absorber, an evaporator, vapor from the evaporator flowing to the absorber to be absorbed by solution therein, a condenser, a generator, vapor from the generator flowing to the condenser to be condensed therein, condensate from the condenser passing to the evaporator, and means to circulate fluid in said system, said means comprising a pump assembly including a pump housing having an inlet and an outlet, an impeller in said housing, a motor for actuating said impeller, means for directing fluid through said motor to effect cooling thereof, a shaft carrying said impeller and connected to said motor, a bearing supporting the shaft in desired position to permit rotation thereof, said bearing including a fixed member and a spring biased axially movable member secured to said shaft, said members having cooperating tapered surfaces, a plurality of parallel recess means in said fixed member tapered surface, and means communicating said pump outlet With said plural recess means whereby a portion of the fluid pumped is directed to said bearing.

2. In an absorption refrigeration system, the combination of an absorber, an evaporator, vapor from the evaporator flowing to the absorber to be absorbed by solution therein, a condenser, a generator, vapor from the generator flowing to the condenser to be condensed therein, condensate from the condenser passing to the evaporator, and means to circulate fluid in said system, said means comprising a pump assembly including a pump housing having an inlet and an outlet, an impeller in said housing, a motor for actuating said impeller, means for directing fluid through said motor to effect cooling thereof, a shaft carrying said impeller and connected to said motor, bearing means supporting the shaft in desired position to permit rotation thereof, said bearing means including first and second bearings on opposite sides of said motor, said first bearing including an inner member fixed to said shaft and having a tapered exterior bearing surface, a cooperating outer member having a tapered inner bearing surface adapted to contact said inner member bearing surface, said outer member being attached to said pump housing, said second bearing including an inner member fixed to said shaft and having a tapered exterior bearing surface, and a cooperating outer member having a tapered inner bearing surface adapted to contact said inner member bearing surface, said second bearing outer member being mounted for limited axial movement in said pump housing, spring means biasing said first and second bear-ing inner and outer member-s into cooperating engagement, a plurality of longitudinally extending recess means in the tapered inner bearing surface of said first and second outer bearing members, bearing land portions terminating the opposite ends of said recesses, passage means in said first and second bearing outer members communicating each of said plural recess means with said pump outlet whereby a portion of the fluid pumped is directed to said first and second tapered bearing surfaces.

References Cited by the Examiner UNITED STATES PATENTS 2,741,990 4/56 White 10387 2,915,886 12/59 Leonard 62-494 2,939,399 6/60 Rutschi 10387 2,961,852 11/60 Burton 62-494 ROBERT A. OLEARY, Primary Examiner. EDWARD J. MICHAEL, Examiner. 

1. IN AN ABSORPTION REFRIGERATION SYSTEM, THE COMBINATION OF AN ABSORBER, AN EVAPORATOR, VAPOR FROM THE EVAPORATOR FLOWING TO THE ABSORBER TO BE ABSORBED BY SOLUTION THEREIN, A CONDENSER, A GENERATOR, VAPOR FROM THE GENERATOR FLOWING TO THE CONDENSER TO BE CONDENSED THEREIN, CONDENSATE FROM THE CONDENSER PASSING TO THE EVAPORATOR, AND MEANS TO CIRCULATE FLUID IN SAID SYSTEM, SAID MEANS COMPRISING A PUMP ASSEMBLY INCLUDING A PUMP HOUSING HAVING AN INLET AND AN OUTLET, AN IMPELLER IN SAID HOUSING, A MOTOR FOR ACTUATING SAID IMPELLER, MEANS FOR DIRECTING FLUID THROUGH SAID MOTOR TO EFFECT COOLING THEREOF, A SHAFT CARRYING SAID IMPELLER AND CONNECTED TO SAID MOTOR, A BEARING SUPPORTING THE SHAFT IN DESIRED POSITION TO PERMIT ROTATION THEREOF, SAID BEARING INCLUDING A FIXED MEMBER AND A SPRING BIASED AXIALLY MOVABLE MEMBER SECURED TO SAID SHAFT, SAID MEMBERS HAVING COOPERATING TAPERED SURFACES, A PLURALITY OF PARALLEL RECESS MEANS IN SAID FIXED MEMBER TAPERED SURFACE, AND MEANS COMMUNICATING SAID PUMP OUTLET WITH SAID PLURAL RECESS MEANS WHEREBY A PORTION OF THE FLUID PUMPED IS DIRECTED TO SAID BEARING. 